arm64: selftests: Fix spelling of 'Mismatch'

The SVE and FPSIMD stress tests have a spelling mistake in the output, fix
it.

Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20210108183144.673-1-broonie@kernel.org


Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>